Greenish-blue anthraquinone dye.



I no. 785,121.

UNITED STATES Patented March 21, 1905.

PAT NT OFFICE.

ROBERT E. SCHMIDT,- OEELBERFELD, GERMANY, 'ASSIGNOR TO FARBEN- FABRIKEN OF ELBERFELI) CO.,'OF NEW YORK, N. Y., A OORPORATION OF NEW YORK.

GREENlSH-BLUE ANTHRAQUINONE- DYE.'

SPECIFICATION forming part of Letters Patent No. 785,121, dated March 21, 1905.

Application filed December 20, 1904.. Serial No. 237,706.

To (all, whom it may concern.-

Be it known that I, Ronnn'r E. SoiiMip'r, v

doctor of philosophy, chemist, residingat El- .berfeld, Germany,-(assignor to the FARBEN- 5 FABRIKEN or ELBIGRFELD 00., of New York,) 1 have invented a new and useful Improvement in New Anthraquinone Dye; and I hereby declare the following to be a clear and exact dc scription'of my invention. 1 My invention relates to the manufacture of a new dyestufl' which can be obtained by treating with formic aldehyde and sulfuric acid the bluedye obtainable by heating 1-3-dibromo- 2-amidoanthraquinone with cuprie ehlorid, ni-

I trobenzene, and sodium acetate and being most probably a hydrazin of the formulas 2ov I I a x/ m) Too /\/NH/ co 1 si- (described in United States Letters Patent No. 77 5,369, dated November 22, 1904.) V

In carrying out my process practically 1 can proceed as follows, the parts being by weight:

Ten 'parts of the above-mentioncd hydrazin,

, obtainable from 1-3dibromO-Q-amidoanthraquinon'e, are dissolved in two hund red parts of sulfuric acid, (66 Baum.) To theresulting solution ten parts of a forty-per-cent. solution of formic aldehyde are slowly added with stirring and taking care that the tem peraturedoes 1 not rise highs 1' than 50 eentigrade. The mix- 4 ture is then heated to 70 to 90 centigrade and stirred at this temperature until flakes of a greenish-blue color are obtained on pouring a test portion into water. (The sulfuric-acid solution of the initial material gives reddishblue flakes on, ,being mixed with water.)

When the-reaction is thus 'pnoved tobe complete, the mass is stirred into two thousand parts of water and the precipitate thus obtained is filteredofl and washed with water. The new dyestuff-is thus obtained in the shape of a greenish-blue paste suitable for dyeing in the vat. After being dried and pulverized the coloring-matter forms a dark-blue powder. It is more easily soluble in boiling quinolin and with a very'marked greener color than 5 5 the initial material. It is dissolved by concentrated sulfuric acid with a brownish olive color, greenish-blue flakes being obtained on pouring this solution: into water.

Upon treatment with hydrosulfite of sodium in an alkaline solution the new product is transformed into its hydro compound, a greenishblue vat being thus obtained which dyes cotton greenish-blue pure and fast shades of agreener tint than those obtained with the aid of the ini- 6 5 tial material. 4

Having now described my invention and in what manner the same is to be performed, what I claim asnew is The herein-described new dy'estuff which 76 y can be prepared by treating with formic aldehyde and sulfuric acidthe product obtainable by heating 1. 3-dibromo-2-amidoanthraquinone with euprie chlorid, nitrobenzene and sodium acetate, which dyestuff forms after being dried and pulverized a dark-blue powder soluble in concentrated sulfuric acid with a brownish-olive color, being transformed into its hydro compound on suitable reduction with hydrosulfiteandcaustic-soda lye, the alkaline solution thus obtained exhibiting the typical properties of a vat which dyes unmordanted cotton greenish-blue shades, substantially as hereinbefore described.

In testimony whereofI have signed my name 5 .in the presence of two subscribing witnesses.

' ROBERT EL'SOHMIDT Witnesses: I OTTO KONIG, HEINR. AHLEFELDER. 

